Organic electroluminescent element, compound for organic electroluminescent element, and light-emitting device, display device, and illumination device using said element

Abstract

An organic electroluminescent element using a compound represented by the following general formula (I) emits dark blue light and has small changes in the chromaticity and in the driving voltage even after driving for a long period of time: wherein R 1 to R 6 ; Q 1 and Q 2 ; X 1 , X 2 , X 3 and X 4 are as defined herein.

The invention claimed is: 
     
       1. An organic electroluminescent element comprising:
 a substrate; 
 a pair of electrodes including an anode and a cathode, disposed on the substrate; and 
 at least one organic layer including a light emitting layer, disposed between the electrodes, 
 wherein at least one kind of compound represented by the following general formula (I) is contained in the any layer of the at least one organic layer: 
 
       
         
           
           
               
               
           
         
         R 1  to R 6  each independently represent a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 1  to R 6  are bonded to each other to form a ring; Q 1  and Q 2  each independently represent a 6-membered aromatic ring or a 6-membered nitrogen-containing aromatic heterocycle; a ring may be further fused with the 6-membered ring represented by Q 1  and Q 2 ; of X 1  to X 4 , either each of X 1  and X 4  represents a single bond, and X 2  and X 3  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 , or each of X 2  and X 3  represents a single bond, and X 1  and X 4  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represents a hydrogen atom or a substituent; wherein general formula (I) satisfies at least one of the following conditions 1 and 2: 
         condition 1 in which the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 1  and the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 2  are different from each other;
 with the proviso that when one of Q 1  or Q 2  is a pyridine group and the other is a phenyl group, X 1  and X 4  are NR 53 , and each R 53  is a phenyl group, then at least one phenyl group of R 53  has at least one substituent; and 
 
         condition 2 in which the linking group represented by one of X 1  and X 2  and the linking group represented by one of X 3  and X 4  are different from each other. 
       
     
     
       2. The organic electroluminescent element according to  claim 1 , wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II-1): 
       
         
           
           
               
               
           
         
         wherein R 11  to R 16  each independently represents a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 11  to R 16  are bonded to each other to form a ring; Q 11  and Q 12  each independently represents a 6-membered aromatic ring or a 6-membered nitrogen-containing aromatic heterocycle; a ring may be further fused with the 6-membered ring represented by Q 11  and Q 12 ; X 11  and X 14  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represents a hydrogen atom or a substituent; wherein general formula (II-1) satisfies at least one of the following conditions 1 and 2: 
         condition 1 in which the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 11  and the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 12  are different from each other;
 with the proviso that when one of Q 11  or Q 12  is a pyridine group and the other is a phenyl group, X 11  and X 14  are NR 53 , and each R 53  is a phenyl group, then at least one phenyl group of R 53  has at least one substituent; and 
 
         condition 2 in which the linking group represented by X 11  and the linking group represented by X 14  are different from each other. 
       
     
     
       3. The organic electroluminescent element according to  claim 2 , wherein the compound represented by the general formula (II-1) is a compound represented by the following general formula (II-2): 
       
         
           
           
               
               
           
         
         wherein R 61  to R 66  each independently represents a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 61  to R 66  are bonded to each other to form a ring; R 67  to R 74  each independently represents a hydrogen atom or a substituent, two adjacent groups out of R 67  to R 74  may be bonded to each other to form a ring structure, but the number of the rings thus formed is 2 or less; X 51  and X 54  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represents a hydrogen atom or a substituent; wherein the linking group represented by X 51  and the linking group represented by X 54  are different from each other. 
       
     
     
       4. The organic electroluminescent element according to  claim 3 , wherein in the general formula (II-2), X 51  and X 54  each independently represent a linking group represented by any one of CR 51 R 52 , NR 53 , and O. 
     
     
       5. The organic electroluminescent element according to  claim 3 , wherein in the general formula (II-2), any one of X 51  and X 54  is a linking group represented by NR 53 , and the other is a linking group represented by any one of CR 51 R 52  and O. 
     
     
       6. The organic electroluminescent element according to  claim 3 , wherein in the general formula (II-2), at least one of R 61  to R 74  and R 51  to R 55  is a substituent having any one of a fluorine atom, an alkyl group, a silyl group, an amino group, and a phenyl group or nitrogen-containing aromatic 6-membered ring having these groups. 
     
     
       7. The organic electroluminescent element according to  claim 1 , wherein the compound represented by the general formula (I) is a compound represented by the following general formula (III-1): 
       
         
           
           
               
               
           
         
         R 21  to R 26  each independently represents a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 51  to R 25  are bonded to each other to form a ring; Q 21  and Q 22  each independently represent a 6-membered aromatic ring or a 6-membered nitrogen-containing aromatic heterocycle; a ring may be further fused with the 6-membered ring represented by Q 12  and Q 22 ; X 22  and X 23  each independently represent a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represent a hydrogen atom or a substituent; wherein general formula (III-1) satisfies at least one of the following conditions 1 and 2; 
         condition 1 in which the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 21  and the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 22  are different from each other; 
         condition 2 in which the linking group represented by X 22  and the linking group represented by X 23  are different from each other. 
       
     
     
       8. The organic electroluminescent element according to  claim 7 , wherein the compound represented by the general formula (III-1) is a compound represented by the following general formula (III-2): 
       
         
           
           
               
               
           
         
         R 81  to R 86  each independently represent a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 61  to R 66  are bonded to each other to form a ring; R 87  to R 94  each independently represent a hydrogen atom or a substituent, two adjacent groups out of R 87  to R 94  may be bonded to each other to form a ring structure, but the number of the rings thus formed is 2 or less; X 51  and X 54  each independently represent a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represent a hydrogen atom or a substituent; wherein the linking group represented by X 52  and the linking group represented by X 53  are different from each other. 
       
     
     
       9. The organic electroluminescent element according to  claim 8 , wherein in the general formula (III-2), X 52  and X 53  each independently represent a linking group represented by any one of CR 51 R 52 , NR 53 , and O. 
     
     
       10. The organic electroluminescent element according to  claim 8 , wherein in the general formula (III-2), any one of X 52  and X 53  is a linking group represented by NR 53 , and the other is a linking group represented by any one of CR 51 R 52  and O. 
     
     
       11. The organic electroluminescent element according to  claim 8 , wherein in the general formula (III-2), at least one of R 81  to R 94  and R 51  to R 55  is a substituent having any one of a fluorine atom, an alkyl group, a silyl group, an amino group, and a phenyl group or nitrogen-containing aromatic 6-membered ring having these groups. 
     
     
       12. The organic electroluminescent element according to  claim 1 , wherein the compound represented by the general formula (I) is a compound represented by the following general formula (IV): 
       
         
           
           
               
               
           
         
         wherein R 31  to R 36  each independently represents a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 31  to R 36  are bonded to each other to form a ring; R 37  to R 40  each independently represents a hydrogen atom or a substituent, two adjacent groups out of R 37  to R 40  may be bonded to each other to form a ring structure, but the number of the rings thus formed is 2 or less; R 41  and R 42  each independently represent a hydrogen atom or a substituent; A 1  to A 4  each independently represent CR 56  or N, and at least one of A 1  to A 4  represents N; R 56  represents a hydrogen atom or a substituent, when two adjacent groups out of A 1  to A 4  are CR 56 , the two R 56 's may be bonded to each other to form a ring structure, but the number of the rings thus formed is 2 or less; X 31  represents a linking group represented by any one of NR 53 , O, S, and SiR 54 R 55 ; R 53  to R 55  each independently represents a hydrogen atom or a substituent. 
       
     
     
       13. The organic electroluminescent element according to  claim 1 , wherein the molecular weight of the compound represented by the general formula (I) is 800 or less. 
     
     
       14. The organic electroluminescent element according to  claim 1 , wherein the compound represented by the general formula (I) is contained in the light emitting layer. 
     
     
       15. The organic electroluminescent element according to  claim 14 , wherein the compound represented by the general formula (I) is a light emitting material contained in the light emitting layer. 
     
     
       16. The organic electroluminescent element according to  claim 15 , wherein the light emitting layer further contains a host material. 
     
     
       17. The organic electroluminescent element according to  claim 16 , wherein the host material has a hydrocarbon fused ring structure having 10 to 50 carbon atoms. 
     
     
       18. The organic electroluminescent element according to  claim 16 , wherein the host material has an anthracene skeleton. 
     
     
       19. The organic electroluminescent element according to  claim 1 , wherein the organic layer containing the compound represented by the general formula (I) is formed by a vacuum deposition process. 
     
     
       20. The organic electroluminescent element according to  claim 1 , wherein the light emitting layer is formed by a wet process. 
     
     
       21. A light emitting device comprising the organic electroluminescent element according to  claim 1 . 
     
     
       22. A display device comprising the organic electroluminescent element according to  claim 1 . 
     
     
       23. An illumination device comprising the organic electroluminescent element according to  claim 1 . 
     
     
       24. A compound represented by the following general formula (I): 
       
         
           
           
               
               
           
         
         wherein R 1  to R 6  each independently represent a hydrogen atom or a substituent, but there is no case where two adjacent groups out of R 1  to R 6  are bonded to each other to form a ring; Q 1  and Q 2  each independently represent a 6-membered aromatic ring or a 6-membered nitrogen-containing aromatic heterocycle; a ring may be further fused with the 6-membered ring represented by Q 1  and Q 2 ; of X 1  to X 4 , either each of X 1  and X 4  represents a single bond, and X 2  and X 3  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 , or each of X 2  and X 3  represents a single bond, and X 1  and X 4  each independently represents a linking group represented by any one of CR 51 R 52 , NR 53 , O, S, and SiR 54 R 55 ; R 51  to R 55  each independently represents a hydrogen atom or a substituent; wherein general formula (I) satisfies at least one of the following conditions 1 and 2: 
         condition 1 in which the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 1  and the number of carbon atoms constituting the 6-membered aromatic ring or the 6-membered nitrogen-containing aromatic heterocycle of Q 2  are different from each other;
 with the proviso that when one of Q 1  or Q 2  is a pyridine group and the other is a phenyl group, X 1  and X 4  are NR 53 , and each R 53  is a phenyl group, then at least one phenyl group of R 53  has at least one substituent; and 
 
         condition 2 in which the linking group represented by one of X 1  and X 2  and the linking group represented by one of X 3  and X 4  are different from each other;
 with the provisos that when one of X 1  or X 4  is NR 53 , the other of X 1  or X 4  is S, and R 53  is a substituted or unsubstituted phenyl group, then the compound represented by general formula (I) has at least one additional substituent; 
 when one of X 1  or X 4  is NR 53 , the other of X 1  or X 4  is S, and R 53  is a substituted or unsubstituted alkyl group, then the compound represented by general formula (I) has at least one additional substituent selected from a fluorine atom, a silyl group and an amino group; and 
 when X 2  is NR 53 , X 3  is S, and R 53  is a substituted or unsubstituted alkyl group, then the compound represented by general formula (I) has at least one additional substituent.